ABSTRACT Proposal Number: CTS 9732223 Principal Investigator: M. Modest LCE: Numerical Study of Turbulence-Radiation Interactions In Reactive Flows Radiative heat transfer plays an important role in most fires as well as in commercial combustion applications, with its effects usually being of the same order of magnitude as those of convective heat transfer, and sometimes dominating the overall heat transfer rates. In much the same way as convection is aided by turbulence, so is radiation, which in the presence of chemical reactions may increase several fold due to turbulence interactions. However, the calculation of such turbulence-radiation interactions is extremely difficult and has to date been neglected in all popular CFD solvers or is treated empirically by arbitrarily lowering the predicted flame temperatures to account for the turbulence-radiation interactions. A promising method for accounting for these interactions is the probability density function (PDF) approach. Unfortunately, the PDF method in its present state of development has a number of shortcomings, which preclude its use in reactive flows. The purpose of this research is to further develop the PDF method to resolve the sharp gradients, which exist in reacting flows, and to model the scalar equations for the interactions. The extension of the PDF method will permit it to be included in established CFD codes. The accuracy of the new method will be verified by comparison with DNS calculations and experimental data. This work is funded as part of the joint NSF/Sandia initiative in Life Cycle Engineering.
